A mentally-ill woman held a knife to her elderly mother's throat in a fit of jealousy after she found out her successful sister was coming home from Canada, Dublin Circuit Criminal Court has heard.

Carol Sanders, 50, formerly of Ralahine, Ballybrack, Co Dublin told her mother, “You have to die”, during the attack at the home they shared in Ballybrack on November 24, 2015.

Sanders, an alcoholic who suffers from a personality disorder, pleaded guilty to producing a weapon in a manner likely to intimidate her mother, Mary Sanders. Two other charges of producing a weapon and an assault charge were taken into account by the court.

John Quirke, BL prosecuting, said that when Sanders' mother told her that her sister and uncle were coming home from Canada she was “agitated and jealous of that fact”.

The court heard Sanders' sister was a successful businesswoman and the visit would coincide with Sanders' birthday, which made her angry.

Mr Quirke said Sanders “flung a dinner plate in rage” upon hearing the news and then rang the sister in Canada saying her mother “had to die and was going to be killed.”

“She then kicked her mother three or four times. She tried to choke her,” Mr Quirke said. “...She then got a carving knife and came at her (mother) in a threatening way. She held her down and held a knife to her throat.”

When her mother managed to move away, Sanders then grabbed another knife and held it close to her mother's chest, saying, “You have to die,” Mr Quirke said.

Mary Sanders managed to get away and alert gardaí. “She stated she was petrified and scared,” Mr Quirke said. She subsequently got a barring order against her daughter.

Defence barrister Michael Bowman, SC, said Sanders had battled with a personality disorder since she was a child and that she became an alcoholic in the last couple of years of her marriage, which broke up in the early 2000s.

After she was arrested, Sanders spent two months in custody in the Dóchas Centre and was currently living in supervised accommodation.

“There has been a sea change,” Mr Bowman said, saying Sanders was now on increased anti-psychotic and anti-anxiety medication and was abstaining from alcohol.

Mr Bowman said Sanders consented to the barring order her mother took against her and was hopeful of re-establishing a relationship with her in the future.

“It was a very frightening incident, but Mrs Sanders suffered no physical injuries as a result of it,” he said. Sanders had also handed up a letter of apology to the court, he added.

Judge Brian O'Callaghan said it was a “very serious charge”.

“Obviously when matters of this nature occur within a family it's even sadder,” he said.